Hey Pat,
In Christine, the wire looks to be a double #18 gauge wire, it is black in color. Since it is not seen I would go to Radio Shack and get a good gauge speaker wire. It will not take anything very heavy.
Also remember the old radio has tubes in it! Once you put power to it it takes sometime for it to come on!
My step grandson went for a ride with me in Christine. He asked does the radio work, I said yes! I turned it on and he said its not working. I said it has tubes in it and has to warm up before it comes on. He had this deer in the headlight look! He then asked does it only play old music? I about peed my pants I laughed so hard!!!
Never under estimate the mind of a child!
Richard D. Hord

super cool diagram, thanks! does that speaker wire run from the radio to the speaker or from the audio chassis to the speaker? i thought the shop manul said from the audio chassis? shop manual is the only place i found info on the radio, my wiring manual and assembly manual don't seem to have any. i'm thinking that at one point there must have been some speakers modded for the back panel and that someone took them out and made the panel stock again. oh a question i forgot, when you pull the metal trap door off from under the radio are you supposed to be able to drop the radio totally out. when i took that panel off i have only about a three inch by three inch square cut out, (and not very neatly) not nearly enough to get the radio out! along with that covered glove box light switch, methinks this again points to a dash replacement somewhere in my cars past.

Hey Patrick! Here is the info on the radio. Maybe this will help.. The speaker lead goes to the audio chassis assembly instead of hooking up directly on the radio. Then it comes back to the back of the radio in that 4 pronged connector. This four page break out of the radio should help you.

Driving, racing or working on cars can be hazardous. The procedures and advice on this website including the message board are opinion only. Squarebirds.org and its webmasters and contributors do not guarantee the correctness of the advice and procedures. The Squarebirds.org and its webmasters assume no liability for any damage, fines, punishment, injury or death resulting from following these procedures or advice. If you do not have the skills or tools to repair your car, please consult a professional. By using this site you agree to hold harmless the Squarebirds.org, its authors and its webmasters from any resulting claim and costs that may occur from using the information found on this site.

Any submissions to this site and any post on this site becomes property of Squarebirds.org . The webmasters reserve the right to edit and modify any submissions to this site. All material on this is site is copyrighted by the Squarebirds.org. Reproduction by any means other than for personal use is strictly prohibited. Permission to use material on this site can be obtained by contacting the webmasters. Copyright 2002-2016 by Squarebirds.org.